Wastewater Treatment Turns Malts into Biofertilizer

The idea of producing biofertilizers through wastewater treatment is nothing new. A Chicago-based brewing company, however, is trying to replicate the process to not only save money but also save the environment.

Muntons Malted Ingredients Inc. is not only the creator of the “Great British Malt”, but also produces ingredients for brewing and baking, as well as breakfast cereals, confectionery and other food products. Muntons’ U.K. parent company is renowned as a leader in sustainable production. Since 2016 it has developed a unique, closed-loop wastewater treatment system that converts 88,000 tons of liquid malt waste into a high- quality biofertilizer at its production plant at Stowmarket in Suffolk, England.

At the heart of the wastewater treatment system is a 499-kilowatt, on-site anaerobic digestion (AD) plant that produces 25 percent of the facility’s electricity. Since it started, it has treated around 33 million gallons of effluent which as generated savings of more than $3.35 million in electricity and waste disposal costs. They have also successfully reduced carbon emissions by up to 800 tons of CO2e.

The malt waste is processed into high quality organic fertilizer, which it distributes to its network of growers so that they can produce the 275,000 tons of barley they need for manufacturing 198,000 tons of Muntons’ malt annually.

The focus on sustainable organic fertilizer came about when Muntons previously assessed that 60 percent of their supply come from crops that were treated with artificial fertilizer. They decided to turn to renewable and natural sources of fertilizer by running their liquid waste through a process of anaerobic digestion (AD) to produce high quality biofertilizer as a substitute for their suppliers to use. This significantly reduced their carbon footprint and improved the quality of their yield.

The use of malt-based biofertilizers has also led to the capture of key ingredients like phosphate that were previously lost with the old method. The high organic content of the new fertilizer also improved soil quality and extended the life of the arable land when it was applied.

The digestate used by Muntons is stabilized to remove low-chemical oxygen demand (COD) effluent, nitrates and phosphorus prior to being released to local waterways in compliance with environmental regulations. The remaining sludge is then pasteurized by HRS Heat Exchangers, which is then turned into biofertilizer.

Muntons asserts that its biofertilizer is higher in nitrogen, potash and sulfur than most other available biosolids, as well as being a good source of phosphate and magnesium. Although their biofertilizer is exclusively supplied to their growers for producing malting barley, Muntons is exploring the idea of selling their fertilizer to a broader market.

Muntons wastewater treatment system is geared towards maximizing efficiency. Even heat generated from their system is recaptured and used in other parts of the process. Pasteurization is kept at a continuous pace because they run their tanks to run at half flow rates to avoid having to wait to build up a stock of digestate.

It is remarkable what companies like Muntons can accomplish when they can devise an efficient and sustainable waste treatment system highlighting what is possible in terms of implementing a circular economy. The resulting biofertilizer that they produce has proven to be a valuable resource for their suppliers. It is successful models like these that should be replicated throughout the world.

If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.

Sources:
http://biomassmagazine.com
https://www.bioenergy-news.com

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